A refrigerant fluid circuit of the above type is known from French patent specification No. FR 2 717 126A. This known circuit also includes means for delivering into the cabin a vehicle air which has undergone heat exchange with the evaporator.
The fluid flow switching means mentioned above enables the circuit to operate in three different configuration modes in which it operates, respectively in: a conventional air conditioning circuit mode using the cooling loop; a heating mode using the heating loop; and a third mode (or "fluid charging" mode), in which the refrigerant fluid is accumulated in the evaporator.
This known type of circuit has the disadvantage that it makes it necessary to provide a large number of components, which is detrimental to standardization and also increases its overall size.